Soluble polyimides based on a novel pyridine-containing diamine m,p-PAPP and various aromatic dianhydrides

Abstract

A novel pyridine-containing aromatic diamine monomer, 4-phenyl-2,6-bis[3-(4-aminophenoxy)phenyl]pyridine (m,p-PAPP), was successfully synthesized by a modified Chichibabin reaction of benzaldehyde and a substituted acetophenone, 3-(4-nitrophenoxy)acetophenone (m,p-NPAP), followed by a reduction of the resulting dinitro compound 4-phenyl-2,6-bis[3-(4-nitrophenoxy)phenyl]pyridine (m,p-PNPP) with Pd/C and hydrazine monohydrate. The aromatic diamine was employed to synthesize a series of pyridine-containing polyimides (PIs) by polycondensation with various aromatic dianhydrides in N,N-dimethylformamide (DMF) via the conventional two-step method, and further thermal or chemical imidization forming PIs. The inherent viscosities of the resulting poly(amic acid)s and PIs were 0.59-0.73 and 0.56-0.68 dL/g; most of the PIs obtained by chemical imidization were readily soluble in common organic solvents such as DMF, N,N-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP), tetrahydrofuran (THF), etc. Meanwhile, strong and flexible PI films were obtained, which had good thermal stability, with the glass transition temperature (T g ) of 204.5-237.4°C and the temperature at 10% weight loss of 527.7-552.0°C in nitrogen atmosphere, as well as outstanding mechanical properties with tensile strengths of 88.6-90.4 MPa, a tensile moduli of 1.04-1.56 GPa, and elongations at break of 7.2-8.7%. The PI films also were found to possess low water uptake of 0.89-0.98%.

Nanosized Silica-Reinforced Maleimido Terminal Triaryl Pyridine Core Polybenzoxazine (nSiO2/PBZ) Nanocomposites

“…1), the appearance of a band at of 942 cm À1 (oxazine) and a band at 1734 cm À1 confirms the presence of C¼O stretching. Figures 2a-f show the 1 H NMR and 13 C NMR spectra of the BZ monomers and confirm the structure of BZs [21,28,29] . Figures 3 and 4 show the UV-Vis and PL properties of benzoxazine monomers.…”

“…The products were confirmed by 1 H-NMR, 13 C-NMR and FT-IR techniques and matched with earlier reported data [28] .…”

Influence of crystalline polyimide hard block on the properties of poly(imide siloxane) copolymers

“…The crystalline polyimide hard block was based on polyimide from 1,3-bis(4-aminophenoxy)benzene (TPER) and 3,3 0 ,4,4 0 -biphenyltetracarboxylic dianhydride (BPDA), which displays a T g at 210 C and a high melting temperature at 395 C and has a very fast crystallization rate [31]. The amorphous polyimide hard block was based on polyimide from 2,2-bis(4-(3,4-dicarboxyphenoxy)phenyl)propane dianhydride (BPADA) and meta-phenylenediamine (m-PDA), which displays a T g at 217 C [32]. The two polyimides have nearly the same T g , which is helpful in understanding the influence of crystalline polyimide hard block on the properties of PISs.…”

Design and preparation of novel fluorescent polyimides containing ortho-linked units and pyridine moieties

“…Specially, the emission intensity of protonated polymer exhibits an acid concentration dependent increase in the concentration range of 0.001-0.1 M. This phenomenon suggests the formation of an aggregate and excimer emission at a high concentration of the acid. Because the pyridine-containing PIs have greater electron affinity and better electrontransporting properties, and offer the possibility of protonation of the lone pair electrons as a way of modifying their properties [17][18][19][20][21][22][23].…”

“…Therefore, the pyridine-containing PIs can increase electron affinity to improve electron-transporting properties and offer the possibility of protonation of the lone pair electrons as a way of modifying their luminescence properties [17][18][19][20][21][22][23]. Liaw and others have synthesized some conjugated polymers containing pyridine in the main chain and these materials exhibit excellent optical properties for the development of polymeric photoelectricity and organic photoluminescence materials [16][17][18][19][20][21][22][23]. However, their products still exhibit some drawbacks, such as insoluble nature and low glass transition temperature, which limit their applications.…”